Polyphase filters can be used to provide a filtered output signal with both balanced phase and balanced amplitude outputs. In one example, a polyphase filter can provide four amplitude balanced outputs with the phases 90° apart (e.g., 0°, 90°, 180°, 270°). Various such filter devices have been designed. One type of polyphase filter design involves planar circuit implementations, such as those used in the integrated circuit (IC) and printed circuit board (PCB) industries. In these embodiments, the designs typically involve intricate, complex connection lines between stages of multi-stage polyphase filters. These designs can be complex due to attempts to balance the phase and amplitude of the outputs of the filter. Unfortunately, these solutions can be expensive and complicated—often involving more than two layers and having unwanted coupling between the signals of the various connection lines. Even at great expense, these attempts may not provide satisfactory amplitude and phase balance, and can be particularly unsatisfactory at high frequency bands. Thus, new and useful devices for improving polyphase filters are now described.